drivers/firewire/core-iso.c

   1 /*
   2  * Isochronous I/O functionality:
   3  *   - Isochronous DMA context management
   4  *   - Isochronous bus resource management (channels, bandwidth), client side
   5  *
   6  * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include <linux/dma-mapping.h>
  24 #include <linux/errno.h>
  25 #include <linux/firewire.h>
  26 #include <linux/firewire-constants.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/vmalloc.h>
  32
  33 #include <asm/byteorder.h>
  34
  35 #include "core.h"
  36
  37 /*
  38  * Isochronous DMA context management
  39  */
  40
  41 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  42                        int page_count, enum dma_data_direction direction)
  43 {
  44         int i, j;
  45         dma_addr_t address;
  46
  47         buffer->page_count = page_count;
  48         buffer->direction = direction;
  49
  50         buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
  51                                 GFP_KERNEL);
  52         if (buffer->pages == NULL)
  53                 goto out;
  54
  55         for (i = 0; i < buffer->page_count; i++) {
  56                 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  57                 if (buffer->pages[i] == NULL)
  58                         goto out_pages;
  59
  60                 address = dma_map_page(card->device, buffer->pages[i],
  61                                        0, PAGE_SIZE, direction);
  62                 if (dma_mapping_error(card->device, address)) {
  63                         __free_page(buffer->pages[i]);
  64                         goto out_pages;
  65                 }
  66                 set_page_private(buffer->pages[i], address);
  67         }
  68
  69         return 0;
  70
  71  out_pages:
  72         for (j = 0; j < i; j++) {
  73                 address = page_private(buffer->pages[j]);
  74                 dma_unmap_page(card->device, address,
  75                                PAGE_SIZE, direction);
  76                 __free_page(buffer->pages[j]);
  77         }
  78         kfree(buffer->pages);
  79  out:
  80         buffer->pages = NULL;
  81
  82         return -ENOMEM;
  83 }
  84 EXPORT_SYMBOL(fw_iso_buffer_init);
  85
  86 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  87 {
  88         unsigned long uaddr;
  89         int i, err;
  90
  91         uaddr = vma->vm_start;
  92         for (i = 0; i < buffer->page_count; i++) {
  93                 err = vm_insert_page(vma, uaddr, buffer->pages[i]);
  94                 if (err)
  95                         return err;
  96
  97                 uaddr += PAGE_SIZE;
  98         }
  99
 100         return 0;
 101 }
 102
 103 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 104                            struct fw_card *card)
 105 {
 106         int i;
 107         dma_addr_t address;
 108
 109         for (i = 0; i < buffer->page_count; i++) {
 110                 address = page_private(buffer->pages[i]);
 111                 dma_unmap_page(card->device, address,
 112                                PAGE_SIZE, buffer->direction);
 113                 __free_page(buffer->pages[i]);
 114         }
 115
 116         kfree(buffer->pages);
 117         buffer->pages = NULL;
 118 }
 119 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 120
 121 /* Convert DMA address to offset into virtually contiguous buffer. */
 122 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 123 {
 124         int i;
 125         dma_addr_t address;
 126         ssize_t offset;
 127
 128         for (i = 0; i < buffer->page_count; i++) {
 129                 address = page_private(buffer->pages[i]);
 130                 offset = (ssize_t)completed - (ssize_t)address;
 131                 if (offset > 0 && offset <= PAGE_SIZE)
 132                         return (i << PAGE_SHIFT) + offset;
 133         }
 134
 135         return 0;
 136 }
 137
 138 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 139                 int type, int channel, int speed, size_t header_size,
 140                 fw_iso_callback_t callback, void *callback_data)
 141 {
 142         struct fw_iso_context *ctx;
 143
 144         ctx = card->driver->allocate_iso_context(card,
 145                                                  type, channel, header_size);
 146         if (IS_ERR(ctx))
 147                 return ctx;
 148
 149         ctx->card = card;
 150         ctx->type = type;
 151         ctx->channel = channel;
 152         ctx->speed = speed;
 153         ctx->header_size = header_size;
 154         ctx->callback.sc = callback;
 155         ctx->callback_data = callback_data;
 156
 157         return ctx;
 158 }
 159 EXPORT_SYMBOL(fw_iso_context_create);
 160
 161 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 162 {
 163         ctx->card->driver->free_iso_context(ctx);
 164 }
 165 EXPORT_SYMBOL(fw_iso_context_destroy);
 166
 167 int fw_iso_context_start(struct fw_iso_context *ctx,
 168                          int cycle, int sync, int tags)
 169 {
 170         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 171 }
 172 EXPORT_SYMBOL(fw_iso_context_start);
 173
 174 int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 175 {
 176         return ctx->card->driver->set_iso_channels(ctx, channels);
 177 }
 178
 179 int fw_iso_context_queue(struct fw_iso_context *ctx,
 180                          struct fw_iso_packet *packet,
 181                          struct fw_iso_buffer *buffer,
 182                          unsigned long payload)
 183 {
 184         return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 185 }
 186 EXPORT_SYMBOL(fw_iso_context_queue);
 187
 188 int fw_iso_context_stop(struct fw_iso_context *ctx)
 189 {
 190         return ctx->card->driver->stop_iso(ctx);
 191 }
 192 EXPORT_SYMBOL(fw_iso_context_stop);
 193
 194 /*
 195  * Isochronous bus resource management (channels, bandwidth), client side
 196  */
 197
 198 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 199                             int bandwidth, bool allocate, __be32 data[2])
 200 {
 201         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 202
 203         /*
 204          * On a 1394a IRM with low contention, try < 1 is enough.
 205          * On a 1394-1995 IRM, we need at least try < 2.
 206          * Let's just do try < 5.
 207          */
 208         for (try = 0; try < 5; try++) {
 209                 new = allocate ? old - bandwidth : old + bandwidth;
 210                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 211                         return -EBUSY;
 212
 213                 data[0] = cpu_to_be32(old);
 214                 data[1] = cpu_to_be32(new);
 215                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 216                                 irm_id, generation, SCODE_100,
 217                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 218                                 data, 8)) {
 219                 case RCODE_GENERATION:
 220                         /* A generation change frees all bandwidth. */
 221                         return allocate ? -EAGAIN : bandwidth;
 222
 223                 case RCODE_COMPLETE:
 224                         if (be32_to_cpup(data) == old)
 225                                 return bandwidth;
 226
 227                         old = be32_to_cpup(data);
 228                         /* Fall through. */
 229                 }
 230         }
 231
 232         return -EIO;
 233 }
 234
 235 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 236                 u32 channels_mask, u64 offset, bool allocate, __be32 data[2])
 237 {
 238         __be32 bit, all, old;
 239         int channel, ret = -EIO, retry = 5;
 240
 241         old = all = allocate ? cpu_to_be32(~0) : 0;
 242
 243         for (channel = 0; channel < 32; channel++) {
 244                 if (!(channels_mask & 1 << channel))
 245                         continue;
 246
 247                 ret = -EBUSY;
 248
 249                 bit = cpu_to_be32(1 << (31 - channel));
 250                 if ((old & bit) != (all & bit))
 251                         continue;
 252
 253                 data[0] = old;
 254                 data[1] = old ^ bit;
 255                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 256                                            irm_id, generation, SCODE_100,
 257                                            offset, data, 8)) {
 258                 case RCODE_GENERATION:
 259                         /* A generation change frees all channels. */
 260                         return allocate ? -EAGAIN : channel;
 261
 262                 case RCODE_COMPLETE:
 263                         if (data[0] == old)
 264                                 return channel;
 265
 266                         old = data[0];
 267
 268                         /* Is the IRM 1394a-2000 compliant? */
 269                         if ((data[0] & bit) == (data[1] & bit))
 270                                 continue;
 271
 272                         /* 1394-1995 IRM, fall through to retry. */
 273                 default:
 274                         if (retry) {
 275                                 retry--;
 276                                 channel--;
 277                         } else {
 278                                 ret = -EIO;
 279                         }
 280                 }
 281         }
 282
 283         return ret;
 284 }
 285
 286 static void deallocate_channel(struct fw_card *card, int irm_id,
 287                                int generation, int channel, __be32 buffer[2])
 288 {
 289         u32 mask;
 290         u64 offset;
 291
 292         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 293         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 294                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 295
 296         manage_channel(card, irm_id, generation, mask, offset, false, buffer);
 297 }
 298
 299 /**
 300  * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 301  *
 302  * In parameters: card, generation, channels_mask, bandwidth, allocate
 303  * Out parameters: channel, bandwidth
 304  * This function blocks (sleeps) during communication with the IRM.
 305  *
 306  * Allocates or deallocates at most one channel out of channels_mask.
 307  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 308  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 309  * channel 0 and LSB for channel 63.)
 310  * Allocates or deallocates as many bandwidth allocation units as specified.
 311  *
 312  * Returns channel < 0 if no channel was allocated or deallocated.
 313  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 314  *
 315  * If generation is stale, deallocations succeed but allocations fail with
 316  * channel = -EAGAIN.
 317  *
 318  * If channel allocation fails, no bandwidth will be allocated either.
 319  * If bandwidth allocation fails, no channel will be allocated either.
 320  * But deallocations of channel and bandwidth are tried independently
 321  * of each other's success.
 322  */
 323 void fw_iso_resource_manage(struct fw_card *card, int generation,
 324                             u64 channels_mask, int *channel, int *bandwidth,
 325                             bool allocate, __be32 buffer[2])
 326 {
 327         u32 channels_hi = channels_mask;        /* channels 31...0 */
 328         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 329         int irm_id, ret, c = -EINVAL;
 330
 331         spin_lock_irq(&card->lock);
 332         irm_id = card->irm_node->node_id;
 333         spin_unlock_irq(&card->lock);
 334
 335         if (channels_hi)
 336                 c = manage_channel(card, irm_id, generation, channels_hi,
 337                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 338                                 allocate, buffer);
 339         if (channels_lo && c < 0) {
 340                 c = manage_channel(card, irm_id, generation, channels_lo,
 341                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 342                                 allocate, buffer);
 343                 if (c >= 0)
 344                         c += 32;
 345         }
 346         *channel = c;
 347
 348         if (allocate && channels_mask != 0 && c < 0)
 349                 *bandwidth = 0;
 350
 351         if (*bandwidth == 0)
 352                 return;
 353
 354         ret = manage_bandwidth(card, irm_id, generation, *bandwidth,
 355                                allocate, buffer);
 356         if (ret < 0)
 357                 *bandwidth = 0;
 358
 359         if (allocate && ret < 0) {
 360                 if (c >= 0)
 361                         deallocate_channel(card, irm_id, generation, c, buffer);
 362                 *channel = ret;
 363         }
 364 }
 365 EXPORT_SYMBOL(fw_iso_resource_manage);